Enhancing lithotripsy efficiency in retrograde intrarenal surgery via a flexible kidney-fixed position: findings from a prospective cohort study.

Retrograde intrarenal surgery (RIRS) is recognized as an effective intervention for renal stones measuring less than 20 mm. This study aims to assess the efficacy and safety of a novel flexible kidney-fixed position compared to the conventional lithotomy position, focusing on lithotripsy efficiency and stone-free rates (SFR). A total of 100 patients undergoing unilateral RIRS between January 2023 and September 2024 were randomly allocated to either the conventional lithotomy position group or the kidney-fixed position group. Comparative analyses were conducted on demographic data, stone characteristics, intraoperative parameters, kidney movement metrics, and postoperative complications. A total of 97 patients successfully completed the study, with 47 participants assigned to the conventional lithotomy group and 49 to the kidney-fixed group. The kidney-fixed position was associated with a significant reduction in kidney movement (4.00 mm compared to 15.30 mm, p < 0.001) and a decrease in operative time (48.35 min versus 71.72 min, p < 0.001). Additionally, the SFR for stones measuring ≤ 4 mm was significantly higher in the kidney-fixed group (91.84% compared to 68.09%, p = 0.020). The implementation of a flexible kidney-fixed position markedly improves the efficacy of lithotripsy during RIRS, resulting in reduced operative time and an elevated SFR without a corresponding increase in postoperative complications. This technique holds promise for advancing the surgical management of renal calculi, warranting further investigation to substantiate these findings and assess long-term outcomes.